Maxim Integrated MAX15301 PMBus Command Set - Manual (Page 23)

MAX15301 PMBus Command Set User’s Guide
Rev 1 Page 23 of 53
IOUT_OC_FAULT_RESPONSE
Reference: Standard Command Lockable: Yes
Command Code: 0x47 Format: Bit field
Data Bytes: 1 Units: N/A
Transfer: Read/Write Byte Factory Value: 0xBF (Shut down, retry every 700ms)
Description/Notes: See Sections 10.5.1 and 15.9 of the PMBus Specification Part II.
For overcurrent faults, the MAX15301 implements the fault responses of PMBus Specification section
10.5.1, rather than the responses of section 10.5.2.
Note that…
• MAX15301 does not support finite, non-zero restart-attempt counts. (Continuous restart
attempts are supported.)
• MAX15301 also does not support the “delay before shutdown” (sometimes referred to as
“wait for abate”) option for overcurrent faults.
The IOUT_OC_FAULT_RESPONSE command data comprises three bit-fields:
Bits [7:6] determine the basic fault-response mode. The MAX15301 supports the following modes:
00 Ignore the fault condition.
01 Same as setting 10.
10 Stop regulating immediately, delay for the time specified in bits [2:0], then attempt to
restart according to bits [5:3]. (Default setting)
11 Same as setting 10.
Bits [5:3] determine the number of retry attempts. The MAX15301 supports only a subset of the full
PMBus functionality for this portion of the command:
000-110 No attempt is made to restart after a fault shutdown.
111 Attempt to restart continuously until commanded off, or until another fault
condition causes the unit to shut down. (Default setting)
Bits [2:0] determine the retry-delay timing. Each binary value in bits [2:0] corresponds to a multiple of
100ms, up to a possible maximum of 111
bin
= 700ms. A value of 000
bin
will cause the MAX15301 to
use the minimum possible timing value, typically about 30-40ms. (The default timing for overcurrent
faults is 700ms.)
OT_FAULT_LIMIT
Reference: Standard Command Lockable: Yes
Command Code: 0x4F Format: Linear
Data Bytes: 2 Units: °C
Transfer: Read/Write Word Factory Value: 0xEB98 (115°C)
Description/Notes: See Section 15.17 of the PMBus Specification Part II.
The MAX15301 has an internal temperature signal and can also measure temperature at an external
location, using a diode junction.
The OT_FAULT_LIMIT applies to the external temperature signal, if a valid sensor is detected during
initialization. If no external sensor is detected, the OT_FAULT_LIMIT applies to the internal